The period in French medicine between the deaths of Francois Xavier Vincent Bichat and Rene Theophile Hyacinthe Laennec was one of considerable growth, both in terms of major contributions to the literature of clinical medicine and in terms of international visibility. The institutional location for much of this growth was Paris and the clinique, and in particular the Faculty of Medicine of Paris. The intellectual location for the new studies of both normal and (especially) disordered structure and function in the human organism was the emerging science of pathological anataomy. Even before the microscope became the main research tool of pathologists, they were confronted with many of the same problems, and generated some of the same general sorts of solutions, as their successors were to do in the second half of the nineteenth century, in the era of cellular pathology. The pathology of inflammation, and the variety of disease processes affecting the serous and other membranes, were of particular interest. Bichat's Treatise on Membranes provided a programmatic text and a research model adopted by the Paris medical community. The present study will examine the history of this research program as it was elaborated by Xavier Bichat's successors and followers. Published works, unpublished manuscript materials, student notes, and post-mortem reports will be examined in an effort at providing a descriptive and, to the extent possible, explanatory framework for the growth of one aspect of the history of nineteenth century medicine.